International Patent Application Publication Number WO 2004/046115 provides certain 4-oxoquinolone compounds that are useful as HIV integrase inhibitors. The compounds are reported to be useful as anti-HIV agents.
International Patent Application Publication Number WO 2005/113508 provides certain specific crystalline forms of one of these 4-oxoquinolone compounds, 6-(3-chloro-2-fluorobenzyl)-1-[(S)-1-hydroxymethyl-2-methylpropyl]-7-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid. The specific crystalline forms are reported to have superior physical and chemical stability compared to other physical forms of the compound.
There is currently a need for improved methods for preparing the 4-oxoquinolone compounds reported in International Patent Application Publication Number WO 2004/046115 and in International Patent Application Publication Number WO 2005/113508. In particular, there is a need for new synthetic methods that are simpler or less expensive to carry out, that provide an increased yield, or that eliminate the use of toxic or costly reagents.